Electronics > Metrology

More voltage references - die pictures

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Noopy:

Hi all!


I don´t want to blow the metrology section apart, so I will post less important references in this topic.


Today I have a LT1009 for you:












I have also done some reverse engineering.

It seems that they can change the reference voltage by changing the metal layer. Most parts of the 6k6-resistors are shorted here.

In the upper right corner there are some parts that are not connected. Perhaps a spare function? A start-up-circuit? It seems that this circuit has also a fusible link.

And I found a small hidden capacitor looking like an F. At least I think it´s a capacitor.

See more at my website:

https://www.richis-lab.de/REF10.htm

 :popcorn:

Noopy:

Today I have a LT1029 for you:

https://richis-lab.de/REF11.htm




The specifications are quite simliar to the LT1009 but the die is much more complex. It seems that it´s based on the LT1019 design because you can read 1019B on the die.




The die could be kelvin connected. The two bondpads placed at the ground potential and the two placed at the v+ potential are isolated from eacht other so you can compensate the bondwire resistance even without kelvin connection outside the package. That seems more intelligent than in the LT1236 where the kelvin connection pads are connected on the die.




A nice bandgap configuration!


You can compensate the temperature drift with the fusible resistors in the bottom left corner that belong to the bandgap circuit. Fusing the resistors in the upper right courner you can adjust the output voltage because they are placed in the feedback path.


 :popcorn:

Andreas:
Hmm,

the LT1019 has a heater pin and a heater resistor (hidden in the newer datasheets).

https://www.datasheetarchive.com/pdf/download.php?id=4628e6e0c37324eca3aefd62a37ec0b715ab84&type=P&term=LT1019-5

the problem is that there is no extra ground pin and the heater current shifts the output voltage due to common impedance effects.

But if its the same die the heater structure should be somewhere visible

With best regards

Andreas

Noopy:

Where did you find a heater in the datasheet?  :-//

Well I think I will have to decap a LT1019...  ;D

Best Regards,

Richard

Andreas:
In the above linked datasheet (old version Rev B) page 2 + page 3 (see PIN 7)

see also AN42 page 15
https://www.analog.com/media/en/technical-documentation/application-notes/an42.pdf

with best regards

Andreas

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